1. Field of the Invention
The present invention relates to a keyboard apparatus having a frame integrally formed by resin and pivotably supporting a plurality of keys, and more particularly, to a keyboard apparatus having hammers supported on a frame so as to each pivot in conjunction with a corresponding key and impart inertia to the key.
2. Description of the Related Art
Conventionally, keyboard apparatuses have been known in which a frame integrally formed by resin and pivotably supporting a plurality of keys is adapted to be supported on a musical instrument main body. Among these, some keyboard apparatus includes hammers supported on the frame and each adapted to pivot in conjunction with a corresponding key and impart inertia to a pivotal motion of the key (Japanese Patent Publication No. 3819136 and Japanese Laid-open Patent Publication No. 9-269783).
In the keyboard apparatuses in Japanese Patent Publication No. 3819136 and Japanese Laid-open Patent Publication No. 9-269783, the hammers are disposed below the keys and each driven by a corresponding key so as to pivot about a hammer support.
These keyboard apparatuses are provided with key-depression sensors for detecting key-depression operations, each sensor being disposed below a corresponding hammer so as to be depressed by the hammer.
The keyboard apparatuses are further provided with initial and end stoppers adapted for contact with the hammers to restrict initial and end positions of pivotal motions of the hammers. Since these stoppers are disposed in a longitudinal direction on the same side with respect to the hammer supports, initial and end stopper-formed portions of the frame must be somewhat differentiated in longitudinal position from each other for ease of die molding of the frame. As a result, the frame becomes long in longitudinal length.
In deed, rear ends of the hammers in Japanese Patent Publication No. 3819136 are more projected rearward than rear ends of the keys, and front ends of the hammers in Japanese Laid-open Patent Publication No. 9-269783 are more projected forward than front ends of the keys. As a result, the key board apparatuses are long in longitudinal length.
Furthermore, since the key-depression sensors are each disposed below the corresponding hammer so as to be depressed by the hammer, a pivotal motion range of the hammers is limited. To attain a sufficient pivotal motion range, the keyboard apparatuses tend to be large in vertical size.
Incidentally, it has been known to configure keys to have key main bodies connected via thin-plate-like hinges to base ends of the keys and arrange the base ends to vertically extend so as to reduce the longitudinal length of keyboard apparatus (Japanese Laid-open Patent Publication No. 2008-26403).
In this keyboard apparatus, however, a suitable construction for keyboard apparatus provided with hammers was not adequately considered, and there is a scope for studying how the keyboard apparatus having hammers can be much more compact in its entirety.